厚层盖层段断层垂向封闭性定量评价方法及其应用OA北大核心CSTPCD

Faults and fractures are primary factors that lead to vertical adjustment migration or leakage of oil and gas(trap failure),but controlling factors of vertical fault seal of different types of caprock intervals are obviously differ-ent,restricting evaluation of vertical fault seal.Taking thick gypsum caprock and mudstone caprock as study ob-ject,and combining with field observation,rock mechanics test and laboratory reservoir analysis,a quantitative evaluation method for caprock brittle-ductile transition is established based on Byerlee friction law,Mohr-Coulomb fracture criterion and Goetze's criterion,revealing the difference of internal structure of fault zones in different brit-tle/ductile caprock intervals and constructing an evaluation method for vertical fault seal in different brittle/ductile caprocks.The results show that the main controlling factors of vertical fault seal in thick gypsum and mudstone cap-rock intervals are caprock brittleness/ductility,deformation mechanism of fault in caprock intervals and vertical sealing capacity.Vertical fault seal of mudstone caprock in brittle area of Anjihaihe Formation in Zhunnan area is quantitatively characterized by fault juxtaposition thickness(HCJT)method,with HCJT critical value of about 400 m.Vertical fault seal of gypsum caprock in brittle/ductile area of southern flank of Dongqiu anticline in Kuqa Depres-sion is quantitatively characterized by shale smear factor(CSSF),with critical value of 3.5～4.0.The research pro-vides important guidance for three-dimensional stereoscopic exploration of fault-block reservoirs in sedimentary ba-sins in China.